Burner



July 14, 1942. w OFELDT 2,289,675

BURNER Fil ed Feb. 24, 1939 I N VEN TOR.

ATTORNEY;

Patented July 14, 1942 BURNER Frank W. Ofeldt, McKeesport, Pa., assignor to Homestead Valve Manufacturing Company, Coraopolis, Pa., a corporation of Pennsylvania Application February 24, 1939, Serial No. 258,201

6 Claims.

This invention relates to burners and particularly to burners of the atomizing type for liquid fuel.

The atomizing burner making up this invention is successfully operating in commercial spray generating apparatus. This burner may be advantageously employed in commercial and domestic heating units and other similar applications wherein a liquid fuel such as oil is burned.

The orifices of atomizing burners frequently clog up due to carbonization, which is caused by improper shielding of the burner jet. The fuel gathers on the jet and is carbonized and if not cleaned frequently will completely close the jet orifice even though the fuel is subjected to a high atomizing pressure.

The principal object of this invention is to provide a shield for an atomizing burner jet for retaining carbonized fuel and preventing it from gathering on the jet adjacent the orifice.

Another object is to provide a primary air mixer for liquid fuel atomizing burners.

Another object of this invention is to provide a flame guiding ring which acts in conjunction with a jet shield for producing the desired shape and propagation of an atomized fuel flame.

Other objects and advantages are apparent in the following description and claims.

A practical embodiment. illustrating the principles of this invention is shown in the accompanying drawing wherein:

Fig. 1 is a vertical section of an atomizing burner assembly.

Fig. 2 is an enlarged view of the burner jet with a shield attached thereto.

Fig. 3 is a view taken on the line 3--3 of Fig. 2. Referring to the drawing, in represents the wall of a combustion chamber having an opening ll therethrough for receiving the neck l2 of the blower housing l3 which is secured to the wall by a plurality of annularly disposed bolts I4. The other end of the burner housing encloses a rotary squirrel cage fan l5 which. draws air through the side of the housing and forces it through the neck [2 into the combustion chamber.

The atomizing nozzle It has a cylindrical body I1 and a substantially spherical nose ill with a single orifice I9 in the center thereof and is threadedly secured to the end of the fuel pipesageway through the valve 24 to the fuel line 25 exteriorly of the housing.

The burner shield 26 is made up of the tubular portion 21 having a flared or bell-shaped end 28 with an annular offset 29 forreceiving the dish member 30 which is welded thereto. The wall of the tubular portion 21 is pressed to form four fiat sides 3| as indicated in Fig. 3 which produce four air passageways 32 in quadrangular relation with the body portion ll of the nozzle and is held on the latter by mere frictional engagement. The hexagonal nut 33 formed on the end of the body portion ll of the nozzle does not interfere with the passageways 32.

The dish portion 30 of the shield has a flat base portion 34 and a flared bell-shaped rim 35 which continues the contour of the bell-shaped portion 28 and terminates in a plane normal to the axis of the orifice. A hole 36 is made in the center of the base of the dish, the diameter of which is less than the full diameter of the spherically shaped nose I8.

31 represents-an electrode assembly secured to the housing l3 and provided with an inwardly disposed electrode 38 electrically insulated from the burner parts and connected to a suitable spark coil through the wire 39. The end of the electrode 38 is so positioned with respect to the rim 35 of the shield that when subjected to a 30 high potential a spark is formed across the gap between the electrode and the shield, the latter formingthe ground return of the circuit. The atomized fuel is ignited by this spark and burns within the annular flame guiding ring 40 in the combustion chamber.

The ring 40 and the shield are made of high quality heat resisting metal. The spark may be produced continuously or during a starting charged. If after long usage the rim 35 of the shield becomes burned one need only to rotate the shield to bring an unused portion of the rim adjacent the electrode.

The ring 40 is supported by the shell 4| which may be made of ordinary sheet metal as the heat will not burn the metal at this portion of the assembly.

In operation the draft created by the fan I5 is forced through the neck l2 and a very small to the nose of the nozzle. Thus air flows over the spherically shaped nose, mixes with atomized fuel issuing from the orifice l8 and passes out through the opening 36 where it is ignited a short distance from the shield which distance is deterperiod when the atomized fuel is being dispercentage is drawn through the passageways 32 mined by the velocity of the fuel. This small portion of air that is mixed with the fuel prior to its ignition is generally called primary air.

the shield as indicated at 42. The shield then deflects the air radially, creating a rolling turbulent action with the rings 40 and 4| which forms the burning fuel into a vortex, the axis of which is a closed curve. The vortex does not contact the ring 40 but rolls out into the combustion chamber until combustion is completed.

When this burner is applied to a spray generating apparatus with a relatively short combustion chamber and stack and is properly adjusted there is no smoke emitted, and complete combustion is effected. The rolling vortex of air together with the atomized fuel produce a hot blow torchtype flame with concentrated heat energy and of substantially the shape shown which may be changed by changing the fuel and air pressures.

The dish 30 of the shield collects all of the carbonized material produced by the flame. The discharge force of the fuel and primary air through the opening 36 in the dish prevent any carbon from forming or settling on the spherically shaped nose of the burner. This is aided by the fact that the opening 36 is smaller than the large diameter of the nose and the flat base portion 34 is placed relatively close to the end of the nose. If the base 34 of the dish were omitted the rolling vortex of secondary air would be produced but the nozzle would soon carbonize and clog the orifice.

I claim:

1. In a liquid fuel atomizing burner the combination of an elongated nozzle having an orifice for emitting fuel from the end thereof, a deflector having a tubular portion which slips over said nozzle and a bell-shaped end extending therebeyond, a plate closing said bell-shaped end disposed normally to the axis thereof and having an opening aligned with said orifice, and the nozzle and the tubular portion being spaced to form a channel for admitting air between the plate and the nozzle which air is discharged through said opening with the fuel.

2. In a liquid fuel atomizing burner, the combination of a forced air passageway arranged to conduct air to the burner, a fluid fuel nozzle disposed axially of the passageway with its nose extending beyond the end thereof, the nozzle having an orifice for emitting fuel from the end thereof into the combustion chamber, a deflector having a bell-shaped end of less diameter than said passageway and a tubular portion which slips over the nozzle for supporting the deflector in front of the mouth of said passageway, a disk closing the throat of the bell-shaped end and spaced from the end of the nozzle, said disk being provided with an orifice aligned with the orifice of the nozzle, and a cylindrical flame guiding ring larger in diameter than said passageway and having a closed end fitting closely around said passageway and spaced from the mouth thereof, said ring extending materially beyond the deflector.

3. A burner structure comprising a nozzle of the hydraulic pressure atomizing type producing a hollow conical spray and having an orifice at the tip thereof, a light metal shield member having an orifice aligned with the orifice of the nozzle, said shield member having a tubular portion arranged to slip over the end of the nozzle to locate the shield member out of contact with the conical spray and in front of the tip of the nozzle, the nozzle and the tubular portion being spaced for admitting a limited amount of air which is discharged through the shield orifice with the fuel to prevent flame impingement on the nozzle.

4. A burner structure comprising a nozzle of the hydraulic pressure atomizing type producing a hollow conical spray and having an orifice at the tip thereof, a light metal shield member having an orifice aligned with the orifice of the nozzle, said shield member having a dished shaped portion and also a tubular portion which is arranged to slip over the end of the nozzle to locate the shield member out of contact with the conical spray and in front of the tip of the nozzle, the nozzle and the tubular portion being spaced for admitting a limited amount of air which is discharged through the shield oriflce with the fuel to prevent flame impingement on the nozzle.

5. In a burner structure, the combination with a combustion chamber, an air tube opening into the combustion chamber, a fuel supply line mounted in the air tube, and a nozzle secured to the fuel line and of the hydraulic pressure atomizing type producing a hollow conical spray in the combustion chamber, of a light substantially fiat shield mounted in front of the nozzle, said shield having an orifice axially aligned with the nozzle to permit the fuel spray to pass without restriction to the combustion chamber and also permit a limited portion of air to pass to the combustion chamber to prevent the formation of carbon on the nozzle structure.

6. In a burner structure, the combination with a combustion chamber, an air tube opening into the combustion chamber, a fuel supply line mounted in the air tube, a nozzle secured to the fuel line and of the hydraulic pressure atomizing type producing a hollow conical spray in the combustion chamber, of a light substantially flat shield mounted in front of the nozzle, said shield having an orifice axially aligned with the nozzle to permit the fuel spray to pass without restriction to the combustion chamber and also permit a limited portion of air to pass to the combustion chamber to prevent the formation of carbon on the nozzle structure, and a flame guiding ring mounted in the combustion chamber surrounding the shield in the mouth of the air tube for cooperating with the shield to shape the flame propagation.

FRANK W. OFELDT. 

